linux-ext4 - Re: hole punching in ext4

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Message-ID: <20130122163811.GB6021@localhost.localdomain>
Date:	Tue, 22 Jan 2013 11:38:11 -0500
From:	Carlos Maiolino <cmaiolino@...hat.com>
To:	"Bradley C. Kuszmaul" <kuszmaul@...il.com>
Cc:	linux-ext4 <linux-ext4@...r.kernel.org>
Subject: Re: hole punching in ext4

Ext4 supports it, and you can use fallocate(2) with flag FALLOC_FL_PUNCH_HOLE to
dealloc space of a specific file (please see `man 2 fallocate` for more info).

You can use `fallocate` cmdline program to test it.

Ex:

fallocate -p -o 1024 -l 4096 <filename>

fallocate is available on ext4 since linux 3.1 afaik

About Enterprise distros, it's usually better to contact the customer support to
get information about availability/supportability of a specific feature.

Cheers

On Tue, Jan 22, 2013 at 09:34:59AM -0500, Bradley C. Kuszmaul wrote:
> Hi,
> 
> Do any of the ext file systems support hole punching?  If so, do the
> redhat distributions support it?  Can someone provide an example of a
> program that punches a hole in a file in an ext4 file system?
> 
> -Bradley
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-- 
Carlos
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